Differential feeding mechanism for sewing-machines.



I. R. MOFFATT.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED .IUNE I4. I912. LIWKUfiI Patented Sept. 5, 1916.

GSHEETS-SHEET I.

I J. R. IVIOFFATT. DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

. APPLICATION FILED JUNE I4. I912. Iwmm,

Patented Sept. 5, 1916.

6 SHEETS-SHEET 2 I. R. IVIOF FATT.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

Patented Sept. 5, 1916.

6 SHEETSSHEET 3.

APPLICATION FILED JUNE 14. I912.

J. R. IVIOFFATT.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JUNE I4. I9I2..

. II. 9 1 Q'KQfi 1 I. Patented Sept. 5, 1916.

6 SHEETS-SHEET 4.

mh/tmeooeb J. R. IVIOFFATT.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

Patented Sept. 5,1916.

6 SHEETS-SHEET 5.

APPLICATION FILED JUNE 14. I912.

J. R. MOFFATT.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JUNE I4. 1912. 1,19,,U51, PatentedSept. 5,1916.

6 SHEETS-SHEET 6.

JAMES F). MOFFA'IT, OF- CHICAGO, ILLINOIS, ASSIGNOR '10 UNION SPECIAL MACHINE I COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

DIFFERENTIAL FEEDING MECHANISMFOR SEWING-MACHINES.

Specification of Letters Patent.

Patented fiept. 5, 121%.

Application filed June 14, 1912. Serial No. 703,650.

The invention relates to new 'and useful improvements in feeding mechanisms for sewing machines, and more. especlally to feeding mechanisms wherein two feed dogs are given independent movements so that the movement of one dog relative to the other may be varied for securing a differen tial feed of the material operated upon.

An object of the invention is to provide a feeding mechanism of the above character, which is so constructed that the feed dog will be positively moved back and forth, and also to provide devices whereby the amount of throw given to the feed dog operating upon the material in advance of the needle, may be varied relative to the amount of throw given to the rear feed dog, which devices are under the "control of the per-- ator.

A further object of the invention is to provide adjustable stops which are so positioned as to be readily manipulated by the operator forvarying the shift of the controlling mechanism r the differential feed do These and other objects will in part be obvious, and will in part be hereinafter more fully described.

In the'drawings which show by way of illustration one-embodiment of the invention; Figure 1 is a front View of a sewing machine embodying my improvements; Fig, 2 is a plan view of the mechanism underneath the work support, the standard being in section; Fig. 3 is an end view-of the machine with the work support removed, and the standard supporting the overhanging arm, omitted; Fig. 4 is a sectional view on the line 4, 4, of Fig. 2; Fig. 5 is a vertical sectional view on the line 5, 5, of Fig. 2, the end bracket for the work support being broken away; Fig. 6 is a perspective view of the main feed bar, the rock shaft therefor, and the feed dog; the feed dog being separated from the feed bar; Fig. 7 is a perspective view of the auxiliary feed bar; Fig. 8 is a perspective view of the auxiliary feed dog; Fig. 9 is a perspective view of the link for operatin the auxiliary feed bar; Fig. 10 is a detall showing in perspective, the arm and connecting bar for shifting the link which operates the auxiliary feed dog; Fig. 11 is a perspective view of the guiding plate of the auxiliary feed bar; Fig. 12 is a perspective view of the upper plate which bears on the main eccentric, which raises and lowers the feed dog; Fig. 13 is a perspective viewof the bracket arm' which extends underneath the eccentric; Fig. 14 is a detail in plan, showin the controlling lever for the differential fried, and the stops therefor; Fig. 15 is a side view of the same.

In the present embodiment of the invention, I have shown the feeding mechanism as applied to a sewing machine consisting of a bed plate 1, from which rises an overhanging arm 2, having a needle head 3 at its free end, in which reciprocates a needle bar 4. The needle bar is reciprocated from a lever 5 which isconnected b a link 6 to an eccentric on the main sha t 7. Said needle bar carries a needle 8. Cotiperating with the needle 8 is a looper 9, which is pivoted to a looper rocker 10, and the looper is oscillated through a link connection 11 attached to the needle lever extension. The bed plate '1 is provided with brackets 12 and 13, which carry a work support 14. The material is held on the work support by a presser foot 15, which is carried by a presser bar 16 mounted on the needle head. These parts are of the usual construction, and will not need further description. For feeding the material across the work support, I have provided a main feeding mechanism, con-' sisting of a main feed dog 17, which is mounted on a feed bar 18. The feed bar 18 is pivoted to a feed rocker 19, which in turn is pivotally supported by a short shaft 20, carried by brackets 21 and 22, formed integral'with the bed plate. The feed rocker 19 is oscillated by an arm 23, which is rigidly connected to the feed rocker, and at its free end'is connected to a link 24 attached to a crank pin 25. The crank pin 25 is adjustably mounted in a radial slot formed in a disk 26 attached to the outer end of the main shaft 7 As the main shaft rotates, the feed rocker will be oscillated, and through its connection with the main feed bar, will cause the same-to move back and forth, thus imparting to the feed dog its feeding movement's.

The main feed bar is raised and lowered by an eccentric 27 carried by the main shaft 7. A plate 28 screwed to the main feed .bar, rests on the upper part of said eccentric, while a bracket arm 29 also attached to the main feed bar, extends underneath said eccentric. The eccentric will therefore, positively raise and lower said main feed bar, and the feed dog carried thereby. The main feed dog, as clearlyshown in Fig. 3, operates substantially on the material in the rear of the needle. As a means for further feeding the material, I have provided an auxiliary feed dog 30.

This auxiliary feed dog 30 is carried by an independent auxiliary feed bar 31 (see Fig.

7). The forward end of the auxiliary feed bar 31, is provided with a supporting head which carries a rib adapted to engage a groove 32 in the shank 33 of the auxiliary feed dog 30. .Said shank is slotted as at 34, and a screw passing through the slot holds the auxiliary feed dog on the auxiliary feed bar, but permits said-auxiliary feed dog to be adjusted vertically thereon. This auxiliary feed bar 31 is placed alongside of the inain feed bar 18 (see Fig. 2). A plate 35 having a depending lip 36 (see Fig. 11) is adapted to be secured to the main feed bar, and overlies the top and side of the auxiliary, feed bar, and thus forms a housing or journal in which the auxiliary feed bar will slide longitudinally of the main feed bar. The plate 28, which is attached to the under side of the main feed bar and rests on the eccentric 27, also extends underneath the auxiliary feed bar. Said auxiliary feed bar at its rear end is also provided with an arm 37, which has a laterally projecting lug 38, shown in dotted lines in Figs. 4-and This lug extends underneath the main feed bar. The lug being disposed at the extreme rear end of the auxiliary feed bar, prevents any tendency of the auxiliary feed bar to swing about the eccentric 27 as a fulcrum,- whenthe auxiliary feed dog is pressed.

of attachment for the main feed bar, to saidfeed rocker. This arm 42-is provided with v a segmental slot 43. The link 40 is formed with spaced ears 44 which extend on each side of the arm 42, and a pin extends through the ears and the slot43. A bar 45 is pivotally attached to the outer end of the pin passmg through the cars 44, and connecting attached to a shaft 47 which is journaled in bearings 48 and 49. The purpose of the shaft47 is to adjust the position of the link .40 relative to the arm 42. This shaft 47 carries an upwardly projecting arm 50. A link 51 is attached to this arm at one end, and at its other end to a lever 52. The lever 52 is fulcrumed at 53, to a bracket 54 which is rigidly attached to the bed plate of the machine. An-arm 55 is rigidly secured to the lever 52, and is formed with an eye 56 at its outer end, to which may be attached a rod 57. The rod 57 at its other end, is connected with a suitable knee shift or treadle, by means of which the lever 52 may be rocked. A coil spring 58 encircles the shaft 47, and is attached at one end to the shaft, while its other end is attached to the hearing 49. This spring is so positioned on the shaft, as to tend to rotate the shaft in such direction as to hold the arm 46 carried by the shaft 47, in its lowermost position, and thus hold the link 40 at a point adjacent the lower end of the segment slot 43, in the arm 42.

A downward movement of the arm 55 will swing the lever 52 in such direction as to oscillate the shaft 47 so as to raise the arm 46, and thus move the pin connecting the link 40 to the arm 42, to a point adjacent the upper end of the slot 43. As a means for limiting the oscillations of the shaft 47, and thereby positioning the point of connection of the link 40 to the arm 42, I have provided two stops. The lever 52 has an, upwardly projecting arm 59. Mounted on the bracket 54, is a cam 60. This cam 60 is pivoted at 61 to thevbra'cket, and is formed with a handle 62. Said cam is formed with an cecentric graduated face 63, which is adapted to be engaged by the arm 59. The arm 59 is formed with a rounded nose 64 where said arm contacts with saideccentric graduated face. A spring 65 holds the cam 60 in various adjusted positions. A screw 66 carried by. the bracket 54, passes through a slot in the cam 60, and may be used for locking said cam in various adjusted positions. The lever 52 is also provided with a second arm 67, which is bent laterally so as to extend across the edge face of the bracket 54. A screw 68 passes through the arm 67 and is so positioned as to engage the side edge of the bracket 54. Said screw is formed with a suitable means for turning the same, and is provided with a locking nut 69 to hold it in various adjusted positions. This screw 68 will limit the downward throw of the arm 65 which will in turn limit the oscillations of the shaft 47 so as to determine the extreme upper position of the connection between the link 40 and the arm 42. The cam 60 will limit the throw of the lever 52 in manner between the link40 and the arm l2. This.

feed bar, are so positioned as to be readily accessible to the operator. When the link 40-is at the lower end of the slot t3, a-less throw will be imparted to the auxiliary feed bar than when said link is shifted so that its connection to the feed rocker is at a point adjacent the upper end of the slot 43, or further removed from the axis of the feed rocker. This slot may be so disposed rela-- v tive to the pivotal connection between the main feed bar and the feed rocker, that the stroke of the auxiliary feed dog relative to the main feed dog may be varied to any desired degree, and thereby the differential feed movement imparted to the fabric being operated upon, varied.

The stroke of the auxiliaryfeed dog relative to the main feed dog may be so adjusted that the fabric will be fed slightly faster in front of the needle, so as to overcome any tendency to stretch, especially when operating upon knit material or said feed dog may be operated so as to full-in or gather the material in front of the needle. It will be seen, that by theabove construction I have provided devices for controlling a difierential feeding mechanism, which devices are extremely simple, and all the operating parts are positive 1n their action. I have also provided stops whereby the shift of the throw of the auxiliary feed bar may be predetermined, and thereby the operator may quickly go from one differential feeding throw to another predetermined difierential feeding throw.

The mechanism for giving the differential throw to the auxiliary feed dog, is not per .96 my invention, but is shown, described and claimed in the application of Russel G.

VVoodWard, Serial No. 567,518, filed July- 17th, 1910. I

It is obvious that minor changes in the details of construction and arrangement of parts may be made, without departing from the spirit of my invention, as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A feeding mechanism for sewing machines including, in combination, amain feed dog, means for moving said main feed dog back and forth including a feed rocker,

an auxiliary feed dog, means for moving said auxiliary feed dog back and forth in-- eluding a shiftable connection with said feed rocker, and means under the control of the operator for shifting said connection to vary the stroke of the auxiliary feed dog,

said shifting means including a rock shaft,

an arm projecting from said ,rock shaft, a link connecting said arm to said shiftable connection between the auxiliary feed dog and the feed rocker, a second arm connected to said rock shaft, a lever, and a second link connecting the last named arm with said lever, whereby said rock shaft may be shifted.

2. A feeding mechanism for sewing machines including, in combination, a main feed dog, means for moving said main feed dog ack and forth including a feed rocker, an uxiliary feed dog, means for moving said auxiliary feed dog back and forth including a shiftable connection with said feed rocker,

and means under the control of the operator.

for shifting said connection to vary the stroke of the auxiliary feed dog, said shifting me ans including a, rock shaft, an arm PIOJGCtlIlg from said rock shaft, a link conwhereby said rock shaft may be shifted, and

stops cooperating with said lever for limiting the movement thereof.

3. A feeding mechanism for sewing Inachines including in combination a main feed dog, means for moving said main feed dog back and forth including a feed rocker, an auxiliary feed dog, means for moving said auxiliary feed dog back and forth including a shiftable connection with the feed rocker, means under the control of the operator for shifting said connection to vary the stroke of the auxiliary feed dog, said shifting means including a lever, a stop screw for limiting the movement of the lever in one direction, and a shiftable cam stop for limiting the movement of the lever in the other direction.

4. A feeding mechanism for sewing machines including in combination, a main feed bar, a feed dog carried thereby, an auxiliary feed bar and an auxiliary feed dog carried thereby, a feed rocker to which said main feed bar is'connected, said feed rocker having a slotted arm, a link pivotally connected to the auxiliary feed bar and having a shiftable connection with said slot, a rock shaft extending underneath the main feed bar, an arm carried by said rock shaft and projecting rearwardly therefrom, a link connecting said arm on the rock shaft with the link for the auxiliary feed bar, a second arm carried by the rock shaft, a lever, connections between said lever and said second lated. 5. A feeding mechan1s m for. sewing machines, including in combrnati a main moving the rock shaft in one direction, and a lever for moving the rock shaft in the opposite direction.

8. A feeding mechanism for sewing Inachines including in combination, a main feed feed dog, a main feed bar carrying saiddog, a main feed bar carrying said feed feed dog, a feed rocker to which said main feed bar is pivotally connected, an auxiliary feed bar, an auxiliary feed dog carried thereby, an arm carried by the feed rocker, a link having a shiftable-connection with said arm and a connection with said auxiliary feed bar, means for shifting the point of connection between said link and said arm, said means including a rock shaft, a spring for moving the rock shaft in one direction, a lever for moving the rock shaft in the other direction, and adjustable stops for determining the movement of the rock shaft.

6. A feeding mechanism for sewing ma-' chines, including in combination a main feed dog, a mainifeed bar carrying said dog, a feed rocker towhich said main feed bar is pivotally connected, an auxiliary feed bar, an auxiliary feed dog carried thereby, an arm carried by the feed rocker, a link having a shiftable connection with said arm and a connection with said auxiliary feed bar, means for shifting the point of connection between said link and said arm, said means including a rock shaft, a lever for operating said rock shaft, a stop screw for limiting the movement of the lever in one direction, and an adjustable cam stop' for limiting the movement of the lever in the opposite direction.

7 A feeding mechanism for sewing machines including in combination a main feed dog, a main feed bar carrying saidfeed dog, a feed rocker to which said main feed bar is pivotally connected, an auxiliary feed bar supported by said main feed bar and movable longitudinally relative thereto, an auxiliary feed dog carried by said auxiliary feed bar, an arm carried by the feed rocker and projecting above the pivotal connection with the main feed bar, a link pivoted to the auxiliary feed bar and having a shiftable connection with said arm, means for shifting the position of said connection, said means including a rock shaft, an arm carried by the rock shaft, a bar pivotally connecting the arm to the link, a spring for dog, a feed rocker to which said main feed bar is pivotally connected, an auxiliary feed bar supported by said main feed bar and movable longitudinally relative thereto, an auxiliary feed dog carried by said auxiliary feed bar, an arm carried by the feed rocker and projecting above the pivotal connection with the main feed bar, a link pivoted to the auxiliary feed bar and having a shiftable connection with said arm, means for shifting the position of said connection, said means including a rock shaft, an arm carried by the rock shaft, a bar pivotally connecting the arm to the link, a spring for moving the rock shaft in one direction, a lever for moving the rock shaft in the opposite direction, and stops for limiting the movement of the rock shaft.

9. A feeding mechanism for sewing machines including in combination, a main feed dog, a main feed bar carrying said feed dog, a feed rocker to which said main feed bar is pivotally connected, an auxiliary feed bar supported by said main feed bar and movable longitudinally relative thereto, an auxiliary feed dog carried by said auxiliary feed bar, an arm carried by the feed rocker and projecting above the pivotal connection with the main feed bar, a link pivoted to the auxiliary feed bar and having a shiftable connection with said arm, means for shifting the position of said connection, said means including a rock shaft, an arm carried by the rock shaft, a bar pivotally connecting the arm to the link, a spring for moving the rock shaft in one direction, a lever for moving the rock shaft in the opposite direction, a screw stop for limiting the movement of the lever in one direction, and an adjustable cam stop for limiting the movement of the lever in the opposite direction.

In testimony whereof I aflix my signature in the presence of two witnesses.

JAMES R. MOFFATT. Witnesses:

O. MCNEIL, A. G. LILLY. 

